Op same place



(No Model.)

W.;W DEAN. TELEPHONE. No. 535,615; Patented.Mau'. 12, 1895.

[N 721mm.

n4: mums PETERS co Pnoruumo" WASHINGTON. v. c.

WILLIAM W. DEAN, OF ST. LOUIS,

MISSOURI, ASSIGNOR TO THE BELL TELEPHONE COMPANY OF MISSOURI, OE SAMEPLACE.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 535,615, dated March12, 1895.

Application filed September 24, 1894, Serial No. 523,968. (No model.)

which are designed to be Worn upon the head of the central-stationoperator to receive calls and attend to the wants of subscribers.

The invention is more particularly designed for that central-officetelephone system known as the Law system.

The invention will be best understood by referring to the accompanyingdrawings forming part of this specification.

Figure 1 is a front elevation of a head telephone constructed inaccordance with my invention. Fig. 2 is a top plan view of the same.Figs. 3 to 17 inclusive, are detail views of the buzzer or signal-givingpart of the apparatus.

In the drawings in which the same marks of reference indicate the sameparts throughout the different views, 20 is an ordinary telephone havingbinding posts 21 and 22, leading into it, and by which the calls ofsubscribers are made audible to the operator.

This telephonic receiver 20 is attached to a permanent magnet 23 bymeans of a screw 24, the permanent magnet in turn being fastened byscrews 25 to a curved or bowed piece 26 of insulating material, whichpasses over the head of the operator. This curved piece 26 is extendeddownwardly at the other end forming an extension 27 upon the lower endof which the buzzer or signal-giving device 28 is located.

In the Law telephone system, a buzzer or instrument is used to indicateto the operator" whether or not the line wire of a subscriber wanted isbusy. When such-line wire is in use, this fact is indicated to theoperator by a single click emitted by the buzzer, and serves as aWarning to the operator not to make the connection. When, however,theline wire wanted is not in use, a buzzing sound will be given by thebuzzer, and the operator will proceed to make the desired connection.The central-office operator touches the terminals of the wires of thesubscriber wanted with a battery plug previous to making the desiredconnection to ascertain whether the line is busy. If the telephone ofthe subscriber wanted is off its hook and his line wire is busy, thecircuitof the bell-magnet of such subscriber is broken by his telephonehook and his bell is therefore out of circuit. now, the central-officeoperator throws her battery to line, it will cause her buzzer to beactuated and to click but once, the direct and return circuits of thebuzzer being completed over the line wires by the telephone hook of thesubscriber wanted. If, however, the telephone of the subscriber wantedis on its hook and his line is not being used, the circuit of hisbell-magnet will be intact, so that when the central-office operatorputs her battery to line to ascertain whether the line is busy, not onlywill the subscribers bell be rung, but the bell-magnet circuit Will bemade and broken by the vibration of the bell-magnets armature, which isarranged to make and break the circuit as it vibrates, after the fashionof a rheotome. This will make and break the circuit of thecentral-office opera-' tors buzzer, and will cause it to buzz, indieating that the line of the subscriber wanted is not in use.

Heretofore the buzzer has been located upon a post upon the switch-boardand adjacent to theoperator, upon whose head is strapped or otherwisesecured a telephonic-receiving appliance for the reception of calls ofsubscribers. This plan has many objections which are obviated by thepresent invention, wherein the signal-giving device andtelephonic-callingappliance are both placed upon the head of theoperator by acompact and convenient arrangement.

The construction of the buzzer in the present instance is novel, and Ishall now proceed to set forth the same. It consists in the first placeof a metallic cylinder 29 open at its top but having at the lower endthereof a contrally perforated head, which is secured in place upon thedownward extension 27 of the curved piece or bow 26 by screws 30. Withinthe interior of this cylindrical part or casing 29, is arranged anelectro-magnet. The electro-magnet consists of a longitudinallyperforated core 31, the ends of which are reduced and screw-threaded.Upon the screw-threads at each end are placed fiat rings 32 and 36respectively, between which and around the core is wound the coils 35 ofthe magnet. The ring 32 has two small holes therein for the leading-inwires to the coil of the magnet to pass through. The core and coil arethen in serted in the cylindrical casing 29 and a nut 33 is placed uponthe screw-threaded lower end of the core, which nut firmly holds thecore and coil in place. Before placing the nut upon the lower end of thecore, a disk of insulating material 34, perforated for the reception ofthe core, is placed in position upon the core and interposed between thenut and the extension 27 and screws 30.

A metallic diaphragm disk 37 is placed over the upper end of the core 31and the upper circular edge of the casing 29. The exterior of the upperpart of the cylindrical casing 29 is provided with a screw-thread, andupon this is screwed a ring 38 having a milled exterior. After this ringis screwed well down upon the screw-threads of the cylindrical casing29, a cap piece 39 is screwed over the dia phragm and upon the upperpart of the said cylindrical casing 29. This cap piecehas an orifice init so as to readily omit the sounds coming from the diaphragm 37. Thecap piece 39 is not screwed down fully upon the edge of the cylindricalcasing, but a slight play is left between the cylindrical casing and cappiece to perm-it vibration of the diaphragm 37. After the cap 39'hasbeen screwed or set to the required position, the ring 38 is screwedagainst it so as to fix the cap piece in place, and prevent it beingturned except when the set-ring 38 is manipulated for this expresspurpose.

Within the longitudinal perforation of the core 31 is arranged a helicalspring 40, the upper end of which bears against the under side of thediaphragm and the lower end of which bears against a screw 41 insertedin the lower end of the said core. By means of this screw, the tensionof the spring 40 may be adjusted and it may be made to bear with more orless force upon the diaphragm 37 so as to regulate the vibration of thediaphragm.

The coil 35 polarizes the core 31 as well as the cylindrical casing 29,which acts as part of the magnet as well asa casing, the upper end ofthe core serving as one pole of the magnet, and the upper circular edgeof the cylindrical casing 29 serving as the other'pole of the magnet,the point where the core and cylindrical casing meet being the neutralpoint of the magnet. It will be seen that this arrangement furnishes anexceedingly compact device thoroughly cased at all points and of smallcompass. At the same time the device is effective in its operation, andadjustable so that the functions of the parts may be adjusted at will.

42 and 43 are the leading-in wires which pass to the coil of the magnetof the buzzer. These leading-in wires are attached respectively tometallic strips 44 and 45 which pass over the upper part of the curvedor bowed insulating piece 26 being arranged along the edge of suchcurved piece. Upon the other ends of said metallic strips 44 and 45, arearranged binding posts 46 and 47 respectively, to which wires areattached leading to the circuit in which the buzzer is placed by theoperator previous to the operator making the connection desired. Thesebinding posts 46 and 47 are arranged upon that side of the head of theoperator from which the Wires leading to the telephonic receiveremanate, leaving the head of the operator at the other side thereof allthenecessary freedom of motion, and allowing the operators right handand arm freedom to make connections without the liability of becomingentangled in the wires passing to the buzzer, which might occur wherethe wires led directly from the buzzer and emanated from the right sideof the head of the operator. The metallic strips 44 and 45' also serveto impart elasticity and resiliency to the curved piece or how 26, and

thereby make it. easy to spring this part over the head of the operatorand have it, by reason of its own resiliency, hold itself in place.

Having fully set forth my invention, what I desire to claim and secureby Letters Patent of the United States is 1. Acentral-office telephonicapparatus consisting of a bowed piece of insulating material adapted tobe sprung over the head of the operator, a telephonic-calling appliancesecured to one end of said bowed piece and constructed to be appliedover one ear of the operator, and an independently-operatedsignal-giving device at the other end of the said bowed piece, adaptedto be placed near by but free from the other car of thejoperator.

2. Acentral-office telephonic apparatus consisting of a bowed piece ofinsulating material, adapted to be sprung over the head of the operator,a telephonic-calling appliance secured to oneend of said bowed piece, asig nal-giving device at the other end of the said bowed piece, metallicstrips electrically connected to and leading from the signal-givingdevice to that end of the bowed piece upon which the telephonic-callingappliance is located, and suitable electrical connections for thetelephonic-calling appliance and the signal-giving device at that end ofthe bowed piece.

3. A telephonic-signaling device consisting of a suitable diaphragm, amagnet for vibrating said diaphragm, a spring for holding said diaphragmin its normal position, and an adjustable screw for regulating thetension of the spring.

4. A telephonic-signaling device consist- IIO ing of a suitable metalliccasing, a core therespring for holding said diaphragm in its norfor inelectrical communication with said casmal position, and an adjustablescrew for ing, a coil between said core and casing, an regulating thetension of the spring. adjustable cap piece for said casing, a dia- Intestimony whereof I have hereunto set I5 5 phragm arranged between saidcap piece and my hand and affixed my seal, this 36. day of the core andcasing, and a set-ring for hold- September, 1894, in the presence of thetwo ing in place the adjustable cap piece. subscribing witnesses.

5. A telephonic-signaling device consist WM. W. DEAN. [L. 8.]

ing of a suitable magnet, an adjustable cap' Witnesses:

IO piece for said magnet, a diaphragm arranged A. O. FOWLER,

between said cap piece and the magnet, a STANLEY STONER.

